Domestic laundry washing machines can be of the top loading or front loading type, according to the arrangement of the opening for the loading and unloading of the clothes from the machine. The existence of two such categories of machines is due to various factors, from among which it is to be remembered the availability of space within the house, the aesthetic needs and, last but not least, the simple preference of the user for one type of laundry washing machine compared to the other.
Generally laundry washing machines are made up of parallelepiped cabinet containing a tub assembly. The such tub assembly includes a container for the washing liquid, or a tub in a strict sense of the word, within which a basket for the laundry is mounted so as to enable it to rotate around a substantially horizontal axis.
In the case of the front loading machines the basket, of a cylindrical form, has an opening in its frontal wall, substantially coaxial with two openings respectively present on the frontal wall of the tub and of the cabinet of the machine. The laundry is thus loaded and unloaded in relation to the basket through such openings that, during the functioning of the machine, are closed by a door, generally of a circular shape.
Inside the cabinet, appropriate means is provided for producing the rotation of the basket, and includes an electric motor, belts and pulleys, a means for the supply and the discharge of the washing liquid from the tub (hydraulic conduits and one or more pumps), and a distributor device for washing agents, able to supply at determined times of the functioning cycle of the laundry washing machine the detergent or other additives inside the tub.
In front loading washing machines of the known type, the detergent distributor, which is usually arranged in the upper part of the cabinet of the machine, has the form of a drawer with several distinct compartments, and has a conduit which connects the drawer vane with the upper zone of the washing tub. The drawing of the detergent from the distributor usually occurs by means of a water flow which conveys the detergent in the tub over a period varying between 60 and 120 seconds. Most of the detergent is of in a time varying within 60" and 120"; most of the detergent is of course drawn in the initial seconds and therefore the detergent concentration in water is initially very high. This detergent, that has not been able to dissolve, mixed with water, deposits in the lowermost parts of the tub, where the duct of the drainage pump, which for hydraulic reasons must be in the lowermost point of the hydraulic system, is arranged as a result an undesirable detergent accumulation in the pipes is formed. For solving this problem, different devices have been proposed, which provide for recirculating a part of the accumulated detergent. See for example patent documents DE-A-2.655.556 and IT-B1.082.306. Such solutions, even if they allow for a partial recovery of the wasted detergent, are often complex and inefficient.
Another important problem, which is typical of known front loading laundry washing machines, is the difficulty in the loading and unloading of laundry.